THE digestive power may be compared to the physical strength. Every individual can without inconvenience carry a certain weight, while any addition to it is accompanied by a proportionate sense of oppression. In the same way, what is called indigestion is often simply a result of excess. The amount of food which each man is capable of digesting with ease has always a limit. This limit bears relation to his age, constitution, state of health, and habits.

For undisturbed digestion two conditions are essential: a proper relation of the aliment to the digestive organs, and a healthy state of the organs themselves. The first is generally within direct control; but, obviously, with the second, this is not the case; and when, as frequently happens, both conditions are imperfectly fulfilled in the same person, more or less dyspepsia ensues.

Bearing in mind these general views, let us examine the influence of particular causes; and first, as regards age. Appetite, or the natural feeling that food is wanted, indicates that the waste of the body requires to be replenished — that the outlay begins to exceed the income. From birth to the moment of dissolution, waste and supply are in active operation. The infant, in consequence of its rapid growth, requires food at short intervals, and the energy of the wasting process is shown by the activity of his excreting organs. So long as growth continues, the same conditions may be observed, but in a lessening degree. When the stature and form of the body are matured, the demands for nutrition are less urgent, and, after middle age, are diminished still more. The practical inference is, that the man of advanced years does not require, and should not take, as much food as the young man.

How this was recognized by a profound thinker, may be read in Cicero's "Essay on Old Age." He expresses himself gratefully that, while advancing years increased his desire for conversation, they had diminished the necessity for food and drink. But such reflections are seldom made, and still more rarely acted upon. At all stages of adult life, but particularly during its decline, the appetite is over stimulated by condiments, and tempted to excess by culinary refinements.[1] Dyspepsia is not the worst result of this. Gout, and still more serious maladies connected with an impure state of blood, closely follow.

Infringements of the laws of digestion are constantly and in many instances unconsciously committed. One man digests with ease an amount of food which would be fatal to the comfort of another. Animal food is easily digested by some persons twice, or even three times daily; while, if taken by others more than once, it is sure to induce suffering. Nevertheless, the diet of persons associated together is apt to be the same, and a sufficient individuality in matters of eating and drinking is seldom observed.

When the general health is impaired from any cause, digestion infallibly suffers. In many instances it is sought to prop up the one by overtaxing the powers of the other, and dyspepsia is often thus permanently added to the old disorder. The proverb, "Custom is second nature," applies to the human constitution. Health may be maintained, by gradual usage, under circumstances which would be disastrous to the novice. In this country, great faults are committed in the relative amount and distribution of meals. Breakfast frequently consists of tea or coffee, with a small proportion of plain bread or toast. This allays the appetite, but is insufficient for the supply of bodily waste during the long interval between breakfast and a late dinner; during which, in many instances, no luncheon is taken. It also often happens that no solid food is taken from dinner time until the following morning, which is an additional reason for a more substantial breakfast.

Experience shows that the delicate stomach suffers severely from these causes. In some instances, the long unemployed organ secretes an excess of mucus, which greatly interferes with digestion. A sufficient amount of food at breakfast has a direct influence on the digestion of dinner; in which process, large quantities of gastric juice—a fluid charged with nitrogenous and other materials—must be suddenly extracted from the blood. No argument is needed to prove that the blood will be better fitted for these demands upon it, if replenished by the absorption of a substantial breakfast. If gastric juice, insufficient in quantity or of bad quality, be supplied, the appetite for dinner exceeds the digestive power, and another material cause of dyspepsia arises. Long: abstinence thus causes the amount of food taken at dinner to be relatively, as well as absolutely, in excess. When a sufficient quantity of nutriment has been taken in the morning, less will be requisite at a later period, and less will be desired.

The distribution of meals in point of time is by many regarded as quite unimportant. Dinner, as has been said, comes late, quickly followed by tea, and sometimes by supper also. This approximation of meals is pernicious, for the human stomach was unquestionably intended to have intervals of rest. The organ should be allowed to act on its contents en masse; to eat constantly like a ruminant animal is altogether unnatural. The health of any individual would speedily break down, were even the proper amount of food taken in equally divided portions at very short intervals.

Continual alteration of the time of meals is another great mistake. Every hour of the day for dinner, from one to eight, will sometimes be ranged through in the course of a single week. Such irregularities may long be endured by the robust stomach, but are very injurious to the weakened organ. In relation to time, all our functions are singularly influenced by habit. Digestion, therefore, will be best performed at the period when the stomach, from habit, expects employment. The kind and quality of food are essential considerations; and these subjects will be considered elsewhere. Adulteration of food is with out doubt a cause of dyspepsia. Inferior articles of diet, such as tough meat or coarse fish, may, in those unaccustomed to them, produce serious inconvenience; and the impurities of water are well known to disorder digestion.

Man inhabits every part of the globe where external influences can be successfully resisted, and, in effecting this, food is an important element. The colder the climate the more animal food and oily substances are requisite; the warmer, the more vegetable diet is suitable. Whale blubber to the warmly clothed Esquimaux, and rice to the naked Negro, are not more necessities of locality than they would be matters of choice. The same indications exist even within European limits. Thus, diet in England and in Italy is essentially different.

The effects of universal communication are nowhere more obvious than on the luxurious table. To furnish the refined cuisine, all climates, both sea and land, are laid under contribution; and the stomach is expected to digest every thing that is put into it. Huddling together such various products, and neglect of the relation between climate and food, are active causes of dyspepsia. The substantial dishes of this country accord badly with the thermometer at ninety degrees; thus, among the English in India, inflexibility in regulating the kind and quantity of food taken is the cause of much ill health.

Under the head of the relation of food to the organs may be placed the effects of insufficient mastication. It is a fruitful source of dyspepsia, and is more frequently caused by haste or carelessness, than inevitable from the want of teeth. The great prevalence of dyspepsia in the United States has been attributed to the rapid and characteristic manner in which meals are there dispatched. In some employments the insufficient time allowed for meals is, for the same reason, a cause of disturbed digestion, and too often gives rise to permanent disease. Besides actual loss, soreness of the teeth or of the gums, sometimes attended by fetid secretions, greatly interferes with mastication. It is most important that solid food should be duly prepared, by chewing, for the action of the stomach; and it is also important that the starchy elements of food be sufficiently submitted to the action of pure saliva.

There are numerous other causes which affect the digestive organs less directly, but no less injuriously. It has been assumed by some writers that the conditions of civilization are incompatible with the highest degree of health. But there is every reason to believe that dyspepsia affects all races. The Laplander is especially subject to water brash; the Maories of New Zealand suffer much from dyspepsia; and the use of bitter substances to promote digestion is known to many savage tribes. The extremes of abstinence and repletion common with savages, their precarious mode of existence, their fits of complete indolence, followed by exhausting fatigue, must cause them a full share of digestive trouble.

The relative superiority in physical strength of civilized over savage nations has been sufficiently proved. Refined and settled habits are not necessarily attended by any physical disadvantages. But it is observable that those who live in towns are most affected by dyspepsia. There it is that the mental powers are most overtasked; and the relation between mind and body, as well as their mutual reactions, disregarded or forgotten. Too large a share of the nervous energy, so necessary for digestion, is expended in mental toil or business anxieties. In many cases, attention to the commonest physical wants is neglected in monotonous pursuits; the appetite for food is disregarded until it no longer exists; exercise is either not taken at all, or is fitful and unseasonable; ventilation is neglected, and a close and polluted atmosphere is breathed. Such is no overdrawn picture of the town life of vast numbers who suffer, more or less, from dyspepsia.

Two habits, smoking and taking snuff, require special notice as causes of dyspepsia. Excessive smoking produces a depressed condition of the system, and a great waste of saliva if the habit of spitting is encouraged. I have met some severe cases of dyspepsia clearly resulting from these causes. Some individuals are unable to acquire the habit of smoking even moderately. Deadly paleness, nausea, vomiting, intermittency of pulse, with great depression of the circulation, come on whenever it is attempted. But this incapacity is exceptional, and so universal is the desire for tobacco, that it seems as if some want of the system is supplied by its use. Smoking has been attacked and defended with much zeal. Its adversaries have strongly urged that the practice is a potent cause of dyspepsia. The late Sir Benjamin Brodie was a great enemy to tobacco. But, as one of his biographers has observed, he appeared in this instance to have departed from the rule by which he was generally guided, to weigh impartially all the facts bearing on an argument. Other names of eminence might be cited in the ranks of those who are strong opponents of smoking. On the other hand, tobacco stands in no want of facts or of able advocates in its favor.

It has been proved, beyond question, that, where men have been exposed to the combined influences of cold and want of food, those who smoked displayed most endurance. Dr. Hammond states that smoking in moderation, if the food be at the same time sufficient, increases the weight of the body.[2] The author of a clever work on physiology states that a cigar after dinner notably assists his digestion.[3] I am often told by patients that the sense of oppression felt after meals is relieved by smoking. The explanation depends on the strong sympathy which exists between the stomach and the salivary glands. One proof of this dependence is that sickness of stomach is commonly attended by salivation. This makes it probable that, when the salivary glands are stimulated by smoking, the gastric glands, in obedience to a sympathetic action, pour out their secretion more freely. But, if a depressing effect on the nervous system is induced by smoking too much, digestion is certain to be impeded. On the whole, smoking is the cause of more harm than good to digestion. That kind of chronic nervous depression which belongs to hard and inveterate smokers is always accompanied by dyspepsia.

The effects of taking snuff are more insidious, as no warning is given by immediate bad consequences. Great snuff takers are often sufferers in the stomach. In addition to the specific effects of tobacco, the continued stimulating and mechanical action of snuff on the mucous membrane of the nose is injurious. Irritation is directly transmitted from the nasal surface to that of the stomach, with which it is continuous. Dry snuffs are more hurtful than moist, as they penetrate farther.

The difficulty of breaking off or even moderating this habit is well known, and the following plan, practised with success by an inveterate snuff taker, is worth mention: Instead of pure snuff, he kept in his box a mixture in equal parts of snuff and powdered valerian root. His theory was, that the valerian repaired the ravages of the snuff upon his nerves, but the more probable explanation of the benefit is, that he consumed much less of the disagreeable compound than he did of pure snuff.

Persons engaged in offices are exposed to a directly exciting cause of indigestion. The stooping posture in which they write, mechanically interferes with the stomach's action. I have even traced well marked dyspepsia to sitting immediately after dinner in a low armchair, so that the body was curved forward and the stomach compressed. In some trades, the pressure of certain implements upon the pit of the stomach, as in the case of curriers, bootmakers, and weavers, produces severe dyspepsia. Many bad cases, attended with water brash, occur among the weavers of Spitalfields.

Self indulgent, luxurious habits, are highly injurious to healthy digestion; but on this threadbare subject it would be mere waste of time to enlarge. Idleness, and the want of a definite pursuit in life, must also rank high in this class of causes. To preserve the general health, occupation is as necessary for the active mind as exercise is for the vigorous body.

The importance in the system of the reproductive functions is such that their exhaustion must, sooner or later, react on the functions of nutrition. Lamentable instances of the results of sexual excess are occasionally met, and dyspepsia is almost invariably one of these. But the injurious effects of a free indulgence of the sexual instincts have been highly colored. Unprincipled men, who prey on the young and the inexperienced, magnify and distort the significance of certain ailments, the treatment of which, in too many instances, passes out of the hands of the regular practitioner.

In youth, the sensations are quickest, and the impressions most fresh and vivid; so that it might be supposed life would be always then most keenly enjoyed. But its earlier years are frequently clouded. An aching desire for change and excitement often destroys present happiness; and, when the desired excitement is unattainable, ennui and a hopeless indolence ensue. Experience convinces me that this condition of mind is but a frequent result of a feeble state of health. This can be often traced to an overstrain of the mental powers -- a strain daily increased among men by a spirit of emulation, fostered and rewarded by the competitive system to an extent formerly unknown. Accomplishments also among girls are made objects of relentless perseverance. In both sexes, at a time when growth is incomplete, and new functions are springing into existence, the mental are developed at the expense of the bodily powers. Nutrition suffers because appetite and digestion are impaired, and the power of the mind itself is weakened. Over-exertion of mind fatigues equally with that of the body. No reasonable doubt can therefore be entertained that thinking is the result of a physical action in the brain. In what may be for convenience termed secretion of thought, demands are made on nutrition just as in bodily exercise. It has been often observed that great thinkers, if healthy, are usually large eaters.

The state of the air we breathe is highly important in relation to dyspepsia. We live at the bottom of an elastic medium, presenting everywhere the same general composition, and exactly adapted to the exigencies of animal life. Any accidental impurity of the atmosphere tends to disturb the balance of health. Oxygenation of blood is the object of respiration; and its replenishment is the object of digestion. On the other hand, the digestive secretions, as well as the nervous energy by which they are governed, depend for their perfection upon the perfect state of the blood. For this reason ill-ventilated workshops and crowded sleeping-rooms among the poor, and the overheated and impure atmosphere of assemblies and public places of amusement among the better classes, are constantly acting causes of dyspepsia.

Many invalids are affected by changes of weather, especially if these changes occur suddenly. Even in the healthy a general feeling of discomfort is caused by easterly winds; and various disorders are greatly aggravated by them. Rheumatic patients are especially susceptible of bad effects from damp or cold winds, and many dyspeptics are hardly less so; an unusually dry atmosphere is equally injurious to others.

As in the case of a change of climate, the quantity and kind of food required are much influenced by season and temperature, and the agency of these in causing dyspepsia is, therefore, not to be wondered at. Some dyspeptics are always better in summer than in autumn or winter, others the reverse; while a great many tell us they suffer more in spring than at any other season.

Our bodies are at all times pervaded by electricity, the condition of which often completely changes. The clear, serene atmosphere is usually charged with positive electricity, and this, by induction, causes our bodies, as well as the earth itself, to be negative. In wet or stormy weather the opposite of this state of things is usual; the atmosphere is negative while our bodies are positive. We are unable in health to detect these electrical changes; but we might reasonably look for their effects when disease had rendered the body less capable of resisting external impressions. The probable effects of electricity, when the health is susceptible, will be again referred to.

We have still to consider instances in which, although the food may be suitable, and the digestive organs healthy, dyspepsia may be induced by an immediate and accidental effect upon the organs, through the influence of the nerves. There are certain sensations, of which nausea is a remarkable instance, not obviously assignable to any of the five senses; and all these sensations seem capable of being excited by mental influence. We are all conscious that the stomach is a region of sympathy; and here Van Helmont places the seat of the soul itself. With the stomach, or with the bowels, easily confounded with it, various passions—as joy, sorrow, compassion, and indignation—have been in all times associated.

It is universally known that bad news received at or preceding a meal will spoil the best appetite. A disagreeable mental impression sometimes even produces severe dyspepsia, with epigastric pain and sense of oppression, nausea, or vomiting. The intimate nervous connection between the stomach and the brain leaves us at no loss to explain this; and probably an arrest of the secretion of gastric juice is the immediate cause; for in the same way the mouth will become dry from a diminished secretion of saliva. Dyspepsia is also produced or aggravated by severe mental exertion immediately after meals, because of the untimely expenditure of nervous power.

Violent bodily exercise when the stomach is full is a well known cause of disturbed digestion; and in this case the disturbance seems mechanical. The motions of the stomach cannot be favorably carried on while its contents are tossed about by rapid movements of the body; for we know it is essential to the due solution of food that it should be all in turn brought into contact with the stomach's surface

A cold bath after a full meal will frequently disturb digestion; and a hot bath either of water or air will do so with still more certainty. Dyspepsia from warm and cold bathing occurs, in each case, on the same principle, but for opposite reasons. It has been proved, from observations on Alexis St. Martin, that congestion of the stomach is most unfavorable to the secretion of gastric juice. Now, the shock of cold bathing produces congestion, by driving the blood from the surface of the body to the viscera; on the other hand, a certain flow of blood to the stomach is equally indispensable, and that would be interfered with by the hot bath, because it draws the blood from the viscera to the surface. Free bloodletting soon after a meal is commonly succeeded by vomiting, and this affords another example of the effect of sudden withdrawal of blood from the digestive organs.

Dyspepsia has the widest range of all diseases because it forms a part of almost every other; and some, as pulmonary consumption, are in many instances preceded by it. In such cases, early attention to the defects of nutrition would often avert a fatal issue. The gravest forms of dyspepsia accompany organic changes in the alimentary tube itself, as cancer and ulcer of the stomach. It cannot be affirmed that simple dyspepsia does not sometimes shorten life, by producing another disease, or even prove fatal of itself; yet it is certain that digestion may be performed with difficulty for many years without more serious results than proverbial suffering and discomfort.—Causes and Treatment of Imperfect Digestion, new edition.

↑Abernethy, in his peculiar style, insists that civilized man "eats and drinks an enormous deal more than is necessary for his wants or welfare. He fills his stomach and bowels with food which actually putrefies in those organs."